The Americans with Disabilities Act passed into law assuring all people an equal opportunity to gain access to all buildings used by the general public. Even with the adoption of this law, non-ambulatory people are generally afforded ingress to all buildings but not necessarily given a protected means of egress from the building during emergency circumstances. During a building emergency, such as a fire, ambulatory and non-ambulatory building occupants, even those who are clear thinking people under normal circumstances, can panic or make irrational decisions, which can result in injury to themselves and others.
Faced with a difficult emergency situation, people many times revert to their most comfortable behavior. In terms of leaving a multi-story building during non-emergency conditions, this means using the elevator. People normally arrive at and depart from the upper floors of the building via the elevator, and most never have used the emergency stair system. Given a typical response to an emergency situation, people will retrace their most familiar path of travel, which usually includes passing in front of the elevators as they attempt to find an escape route from the building.
During an emergency situation, elevators are usually taken out of service except for controlled use by the fire department. Accordingly, the building occupants cannot currently use the elevator as a safe and reliable means of egress during the emergency situation, such as a fire. They must therefore attempt either to use an unfamiliar stairway or wait within the building to be rescued. Non-ambulatory and disabled people unable to use stairs have no choice but to await help.
In multiple level buildings it is difficult to evacuate building occupants via the stairs. Generally, there are two classifications of buildings relative to fire and life safety: high-rise buildings and mid-rise buildings. The major distinction is that a standard hook and ladder type fire apparatus can only reach the point of a building about 75 feet or 6 floors above the ground, so "high-rise" buildings, those above about 6 floors, must be evacuated from within the building.
In mid-rise buildings, fire departments use the stairs to transport personnel and equipment to the fire floor, which drastically interferes with the designed egress capacity of the exit stair system. In high-rise buildings, the difficulties with occupant evacuation are compounded. Although the elevator cars can be used by the fire department to transport personnel to a selected staging floor below the fire floor, many times smoke is present in the hoistway shaft by the time of their arrival to the staging floor. Stack effect pressures within the building move large volumes of air through the vertical hoistway shafts. The shafts quickly become smoke filled chimneys and are often capable of transporting smoke throughout the building in a matter of minutes.
Since the fire department cannot reach the building's upper floors from outside the building, the building's occupants are forced to either use an exit stairway to evacuate or remain in the burning building until rescued by the fire department. As the fire department personnel uses one stairway to advance on the fire, the stairway doors are typically propped open with fire hoses, thereby allowing smoke from the fire floor to enter the stairway. Accordingly, that stairway is not suitable for evacuation of the building occupants during an emergency.
The evacuation of people is the primary responsibility of the fire department. The fire department personnel do not begin a fire attack until the building occupants are safe. Conventional evacuation of building occupants, however, is a very time consuming process. During a fire, the chaotic environment increases the complexity and danger of an evacuation procedure, which also usually increases the time required to evacuate the building. It is even more difficult and time consuming to evacuate the non-ambulatory, injured, and disabled occupants.
Even if available for use, conventional elevator systems are an unreliable method of escaping a building fire, and under current regulations, can only be used by the fire department under a narrow range of conditions. For example, the elevator system is not used when there is a high risk of a power outage, because such a power outage will shut the elevator system down and potentially trap passengers between floors. The conventional elevator control system is also easily short circuited by water that enters either the machine room or the hoistway shaft. Smoke is easily drawn into the hoistway shaft by naturally occurring stack effect pressures, and the smoke can quickly fill the hoistway, thereby creating an unsafe environment for people without self-contained breathing devices.
Therefore, the elevators are not usable for building occupants as a reliable means of egress during a building fire. Placards stating "Do not use Elevators during a Fire" are commonly placed next to the hall call stations to notify the occupants of the proper emergency exiting strategy. Ambulatory occupants are therefore forced to use exit stairways to escape a building fire, even from the top floors of mega high-rise buildings.